The present invention relates to underground storage of water and more specifically to a system and method which directs water to underground storage zones having available storage capacity. The presently disclosed system and method further may be directed toward water storage in land where the land surface is utilized for other purposes, such as for agricultural use, thereby making efficient use of the land by allowing the concurrent use of the surface and subsurface.
Underground water storage reservoirs provide an alternative to storage of water in open reservoirs. Underground water storage reservoirs, i.e., aquifers, will have one or more porous and permeable layers. Porosity and permeability are the aquifer properties which, respectively, refer to the pore volume available for water storage and the hydraulic conductivity of the aquifer. For utilization for underground water storage, an underground zone must have available pore space and water must be able to flow through the zone to be recovered for utilization for irrigation or other use.
In some regions, water is allowed to accumulate in holding ponds and filter downward into underground storage reservoirs. However, this method of storage has several disadvantages. For example, this method requires the dedication of a land surface area for the holding pond. As another disadvantage, this method results in the loss of water through evaporation as the water slowly filters through the surface soil into the underground storage zones. As another disadvantage, it can be difficult to ascertain where the water has gone and whether the underground storage zones are approaching capacity.
Some underground water storage facilities address water loss through by evaporation by introducing the water into the underground reservoir by piping systems rather than simply allowing the water to enter the underground storage zones by filtration. This type of system expedites introduction of the water into the aquifer and thereby reduces evaporation losses. However, depending upon the design of the water storage facility, the underground reservoir may still require the dedication of significant areas of real property. Moreover, such systems do not, without additional control mechanisms or structure, identify the particular zones or depth into which the water is introduced. Identifying the zones or depth into which the water is introduced can be a significant issue if the underground water storage facility is beneath a land surface utilized for agricultural purposes because saturation of the root-zone can be detrimental to the health of a crop.